/**
 * Copyright (C) 2002-2015   The FreeCol Team
 * <p>
 * This file is part of FreeCol.
 * <p>
 * FreeCol is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 * <p>
 * FreeCol is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * <p>
 * You should have received a copy of the GNU General Public License
 * along with FreeCol.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.sf.freecol.client.gui;

import java.lang.reflect.InvocationTargetException;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.swing.SwingUtilities;

import net.sf.freecol.FreeCol;
import net.sf.freecol.common.model.Direction;


/**
 * Scrolls the view of the Map by moving its focus.
 */
public class ScrollThread extends Thread
{

    private static final Logger logger = Logger.getLogger( ScrollThread.class.getName( ) );

    /** Delay between scroll steps. */
    private static final int SCROLL_DELAY = 100; // ms

    /** The Canvas containing the map to scroll. */
    private final Canvas canvas;

    /** The direction to scroll in. */
    private Direction direction = null;


    /**
     * The constructor to use.
     *
     * @param canvas The Canvas containing the map to scroll.
     */
    public ScrollThread( Canvas canvas )
    {
        super( FreeCol.CLIENT_THREAD + "Mouse scroller" );
        this.canvas = canvas;
    }

    /**
     * Sets the direction in which this ScrollThread will scroll.
     *
     * @param d The <code>Direction</code> in which this ScrollThread
     *     will scroll.
     */
    public void setDirection( Direction d )
    {
        direction = d;
    }

    /**
     * Performs the actual scrolling.
     * Run until interrupted or scrolling fails.
     */
    @Override
    public void run( )
    {
        while ( direction != null )
        {
            try
            {
                SwingUtilities.invokeAndWait( ( ) ->
                                              {
                                                  if ( ! canvas.scrollMap( direction ) ) direction = null;
                                              } );
            }
            catch ( InvocationTargetException e )
            {
                logger.log( Level.WARNING, "Scroll thread caught error", e );
                break;
            }
            catch ( InterruptedException e )
            {
                break; // It is normal for AbstractCanvasListener to interrupt.
            }

            try
            {
                sleep( SCROLL_DELAY );
            }
            catch ( InterruptedException e )
            {
                break;
            }
        }
    }
}
